make DynamicMetaObject related functionality (which depends on private qt includes) opt-in
make DynamicMetaObject related functionality (which depends on private qt includes) opt-in

depending on private headers forces rebuilds on _every_ release

also, since Qt 5.8 the required private include
(which worked standalone before)
added further private includes itself
effectively making the complete qt source code a requirement

knossos-project/PythonQt,knossos-project/PythonQt,knossos-project/PythonQt